Meteorology Frequently Asked Questions

This page last reviewed March 23, 2010

The following is a list of common questions and their answers associated with Meteorology.

General

1. Why is it a No-Burn day when it's sunny outside?
2. Can I get a variance on a No-Burn day?
3. Where can I find the current and historical burn decision?
4. Who do I call if I see smoke impacts in my area?
5. Where can I check the Air Quality Index (AQI) forecast for my area?

District

1. What are the phone numbers for the local Air Districts?
2. Where can I find a list of Air District websites?
3. Where is a map of the Air Districts?

Definitions

1. What is an Inversion?
2. What is a Marginal burn day?
3. What is an Air Basin, Air District?
4. What is AQMIS
5. What is PFIRS
6. What is AQI
7. What is SMP
8. What is title 17
9. What is CB-3
10. What is NWS
11. What is CANSAC

Weather

1. What sites can I look at for general weather 101 ?
2. NWS sites?
3. What are the different model outputs?

General

1. Why is it a No-Burn day when it's sunny outside? Visual sky conditions have little to do with burn day determination. Burn days are forecast using both vertical and horizonal dispersal conditions, not by how cloudy or how sunny it is outside.
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2. Can I get a variance on a No-Burn day? Variances can be given to a person wanting to burn on a no burn day by the local air district, not the ARB. An economic reason must be given for this request.
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3. Where can I find the current and historical burn decision? You can find historic information on ARB's web site.
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4. Who do I call if I see smoke impacts in my area? Complaints about smoke exposure may be directed to the ARB via email or by calling ARB's Complaint Recorder at (800) 952-5588. Please be sure to leave your name, phone number, address and nature of your complaint -- including the date and time. You may also contact your local air district
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5. Where can I check the Air Quality Index (AQI) forecast for my area? For detailed information, about the AQI and AQI levels in your area, please visit the U.S. EPA's AirNow website.
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District

1. What are the phone numbers for the local Air Districts? Here are the phone numbers to the local districts
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2. Where can I find a list of Air District websites? Here is the list of Air District websites.
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3. Where is a map of the Air District? Here is a map of Air Districts.

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Definitions

1. What is an Inversion? The term "temperature inversion" literally refers to a reversal of normal vertical temperature patterns seen in our lower atmosphere. Temperature inversions are relatively common in valley areas. In wintertime, a temperature inversion occurs when cold air close to the ground is trapped by a layer of warmer air. As the inversion continues, air to the ground becomes stagnant and pollution becomes trapped close Inversions also occur during the summer months, but are a product of even hotter upper air trapping warm air close to the ground. The result is the same: we are unable to rid ourselves of the everyday pollution that we create. Air pollution will continue to accumulate until the weather pattern changes.
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2. What is a Marginal Burn day? A marginal burn day is declared when atmospheric conditons are not as condusive to the dispersing of particulate matter as during an open burn day. ARB will check meteorolological conditions and particulate matter readings to determine the dispersal capacity of the atmosphere and will declare a marginal burn day those days when conditons are not suited for an open burn day, but are better than those governing a no burn day.
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3. What is an Air Basin, Air District? A land area with generally similar meteorological and geographic conditions throughout. To the extent possible, air basin boundaries are defined along political boundary lines and include both the source and receptor areas. California is currently divided into 15 air basins. Air District: A political body responsible for managing air quality on a regional or county basis. California is currently divided into 35 air districts. See also air pollution control district and air quality management district.
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4. What is AQMIS? Air Quality and Meteorological Information System (AQMIS): The Air Quality and Meteorological Information System (AQMIS) is a web-based source for real-time (and historical) air quality and meteorological data. AQMIS is used by state and local officials and the public to track air quality. It also supports smoke management and air pollution forecasting.
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5. What is PFIRS? Prescribed Fire Incident Reporting System (PFIRS) serves as an interface between air quality managers, land management agencies and individuals that conduct prescribed burning in California. The website will facilitate communications by providing access to a database containing information on burn planning, burn approvals and emissions information. Once complete, PFIRS will enable individuals involved in prescribed burning the ability to assimilate this information on a statewide level.
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6. What is AQI? The Air Quality Index (AQI), (formerly known as the Pollutant Standards Index) was issued on July 23, 1999 by the U.S. EPA for daily air quality reporting to the public. This new index reflects revisions to the primary health-based national ambient air quality standards for ground-level ozone and particulate matter issued by U.S. EPA in 1997. For much more detailed information, about the AQI and AQI levels in your area, please visit the U.S. EPA's AirNow website
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7. What is title SMP? Smoke Management Program addresses potentially harmful smoke impacts from agricultural, forest and range land management burning operations. The legal basis of the program is found in the Smoke Management Guidelines for Agricultural and Prescribed Burning adopted by the California Air Resources Board (ARB) at its meeting on March 23, 2000. The Guidelines provide the framework for State and local air district regulators to conduct the program. Elements of the program include. Smoke Management Plan (SMP) means a document prepared for each fire by land managers or fire managers that provides the information and procedures required in section 80160 of the Health and Safety Code.
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8. What is title 17? Title 17 is the California Code of Regulations section governing public health and air quality.
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9. What is CB-3? The CB-3 is the Controlled Burn Notice form, otherwise known as the CB-3, is used by districts who elect to have the ARB Meteorology Section provide forecasts or decisions for prescribed burns.
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10. What is NWS? NWS stands for National Weather Service.
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11. What is CANSAC? The California and Nevada Smoke and Air Committee (CANSAC): CANSAC provides experimental forecast products of fire weather, smoke dispersion/transport, fire danger and fire behavior.
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Weather

1. For general weather 101 
2. National Weather Service sites
3. The different model outputs



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